package thread;

import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

public class ThreadPoolDemo {
    /*
    线程池
    主要解决两个问题
    1：重用线程
    2；控制线程数量
     */
    public static void main(String[] args) {
        //创建线程池
        //创建固定大小的线程池，容量为2(内部有两条线程)
        ExecutorService pool = Executors.newFixedThreadPool(2);


        for (int i = 0; i < 5; i++) {
            Runnable r = new Runnable() {
                @Override
                public void run() {

                    Thread t = Thread.currentThread();
                    System.out.println(t.getName() + "正在执行任务...");
                    try {
                        Thread.sleep(3000);
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                    System.out.println(t.getName() + "任务执行完毕。");
                }
            };
            pool.execute(r);
            System.out.println("指派了任务给线程池");
        }
        pool.shutdown();//当前指派任务全部执行完毕就会停止
        //pool.shutdownNow();//立刻停止当前线程 沉睡的线程也会被唤醒 终止
        System.out.println("线程池停止了");


    }
}
